Tunable emission of LiSrCaSiON/:Eu phosphors based on anion substitution induction for WLEDs and optical thermometry.

Polychromatic emission can be achieved by controlling the distribution of the rare earth activator in multi-cation lattices, which can be used in the fields of white light LED and fluorescence temperature sensing. However, it is still a challenge to control their distribution and location of the target site in a given host material because the distribution of the rare earth activator is uncertain. In this paper, we have chosen LiSrCa(SiO) as the multi-cation site host and induced the distribution of Eu ions between different cation sites through anion substitution, for the first time, to regulate the luminescence characteristics of a series of LiSrCaSiON:Eu phosphors. In LiSrCa(SiO):Eu phosphors, the substitution of O by N triggered a distinct ordered to disordered structure transition of the SiO tetrahedron and induced the remote distribution of the Eu activator, which was verified through the analysis of the XRD, EPR, FT-IR and fluorescence spectra. Due to the location of Eu ions in different cation sites (Eu and Eu), two distinguishable emission peaks with tunable color emissions and different responses to temperature were realized. The white LED that utilized blue-orange-emitting LiSrCaSiON:Eu and green-emitting BaSiON:Eu (500 nm) displayed an outstanding color rendering index () of 85.1. Based on the fluorescence intensity ratio (FIR) technique, an optical temperature measurement mechanism was hypothesized and studied in the temperature range of 293-473 K. The highest of the material was 0.086 K, and was 1.76% K based on the FIR detection technology, revealing obviously better than most inorganic optical temperature-measuring materials reported before. Our work indicates that LiSrCaSiON:Eu is a promising material for application in White LEDs and optical thermometers.